| Molecular springs and molecular gyroscope, two diverse topics, are the subject of this dissertation. In Part I oligothiophenes are used as the bases of the molecular spring. The design is targeted in making non-ladder type helix with large extension range. Two non-transition metal cross-coupling strategies for assembling odd- and even-numbered helical oligoarenes are reported. Outer Valence Green Function predicts that the energies of the HOMO and LUMO vary non-linearly with extension from contracted form to extended form. Coupled with recent developments in STM, these molecules should be excellent candidates to demonstrate force-induced attenuation of conductivity. In part II, a non-gearing rotor composed of two nearly orthogonal rotational axes is analyzed by molecular dynamics and ab initio calculations. The isolated system is investigated for its ability to rotate and precess analogous to a conventional gyroscope. We find that correlated rotation and precession at equilibrium is possible, contingent on symmetry, steric, and rotor mass prerequisites. Ab initio frequency calculations can be used to predict the likelihood of a molecular gyroscope to exhibit correlated rotation and precession at equilibrium. |
